It’s a phrase not commonly associated with legal doctrine: returning America to “a place of godliness.”

And yet when asked by a woman posing as a Catholic conservative at a dinner last week, Justice Samuel A. Alito Jr. appeared to endorse the idea. The unguarded moment added to calls for greater scrutiny by Democrats, many of whom are eager to open official investigations into outside influence at the Supreme Court.

But the core of the idea expressed to Mr. Alito, that the country must fight the decline of Christianity in public life, goes beyond the questions of bias and influence at the nation’s highest court. An array of conservatives, including antiabortion activists, church leaders and conservative state legislators, has openly embraced the idea that American democracy needs to be grounded in Christian values and guarded against the rise of secular culture.

They are right-wing Catholics and evangelicals who oppose abortion, same-sex marriage, transgender rights and what they see as the dominance of liberal views in school curriculums. And they’ve become a crucial segment of former President Donald J. Trump’s political coalition, intermingled with the MAGA movement that boosted him to the White House and that hopes to do so once again in November.

The movement’s rise has been evident across the country since Mr. Trump lost re-election in 2020. The National Association of Christian Lawmakers formed to advance Christian values and legislation among elected officials. This week in Indianapolis, delegates to the Southern Baptist Convention, the largest Protestant denomination in America, are voting on issues like restricting in vitro fertilization and further limiting women from pastoral positions.

And in Congress, Mike Johnson, a man with deep roots in this movement and the Alliance Defending Freedom, a conservative Christian legal advocacy group, is now speaker of the House.